The Hypertension optimal treatment international study (HOT) renal substudy is a prospective, randomized, multicenter trial in which patients with hypertension are randomized to one of three diastolic blood pressure target groups: 90, 85, or 80 mm Hg. Renal function is measured at baseline and at two years to determine if there is a difference between races at similar levels of diastolic blood pressure, and if there is a difference in function at different levels of blood pressure.